1. Field of the Invention
Priority is claimed on Japanese Patent Application No. 2004-317951, filed Nov. 1, 2004, the content of which is incorporated herein by reference.
The present invention relates to an electrical connector. In particular, the invention relates to an electrical connector having a locking mechanism for maintaining engagement between two connectors, one of which is a base connector fixed to a print board and the other of which is a socket connector inserted into and removed from the base connector.
2. Description of the Related Art
Nowadays, a compact-sized portable electronic device such as DSC (Digital Still Camera), cellular phone, CD player, or MD player incorporates a battery. To supply electric power from the battery to a circuit board (print board) installed in said electronic device, an extremely small connector, so called CSP (Chip Size Package) type wire to board connector, has been employed.
An electrical connector has been invented in which one ends of lead wires extending from the battery are attached to a socket connector like the above-mentioned socket connector and a base connector like the above-mentioned base connector is fixed to a print board. Further, this electrical connector is designed to avoid a problematic situation where the insertion/removal directions of the socket connector and the direction of extension of the lead wires are different when the lead wires are pulled away to remove the socket connector from the base connector, thereby causing the connectors to tend to be broken by prying damage on these connectors (e.g., refer to Patent document 1).
In the electrical connector according to Patent document 1, when the lead wires are pulled away, the cam face of the base connector and the cam face of the socket connector act together to convert the pulling force to a force along the insertion/removal directions of the socket connector. Further, in the electrical connector, the socket connector is provided with socket contacts for applying a contact force in such a manner that a pair of contact strips on the socket contact sandwich a plane opponent contact from both sides of the opponent contact.
[Patent Document 1]
    Japanese Unexamined Patent Publication 2002-33150
FIG. 17 is a general perspective view of the base connector according to Patent document 1. Further, FIG. 17 of this application corresponds to FIG. 1 of Patent document 1. FIG. 18 is a general perspective view of the socket connector according to Patent document 1. Further, FIG. 18 of this application corresponds to FIG. 2 of Patent document 1. Moreover, FIG. 19 is a vertical cross-sectional view of both connectors in a mated condition in Patent document 1. In FIG. 19, hatching of the socket contact and plane connection terminals is omitted. Further, FIG. 19 of this application corresponds to FIG. 9 of Patent document 1. FIG. 20 is a front view of the socket connector according to Patent document 1. Further, FIG. 20 of this application corresponds to FIG. 8 of Patent document 1.
A conventional electrical connector (hereinafter, referred to simply as connector) 100 comprises a base connector 6 solder-bonded to an attachment face 51 of a print board 5 and a socket connector 7 forming a pair with the base connector 6 and inserted into/removed from a recess (space for insertion/removal) 61 of the base connector 6.
In FIG. 17 and FIG. 18, the recess 61 of the base connector 6 is open in a direction perpendicular to an attachment face 51 of the print board 5 and away from the attachment face 51 (corresponding to the removal direction X2 of FIG. 17), and is also open in one out of two opposite directions parallel to the attachment face 51, i.e., in a front direction Y. The socket connector 7 is inserted into and removed from the recess 61 of the base connector 6 in an insertion direction X1 and a removal direction X2 perpendicular to the attachment face 51. The socket connector 7 is provided with lead wires 9w as an electrical conductor extending generally in the front direction Y.
When the socket connector 7 is removed from the base connector 6, the lead wires 9w are in some cases pulled in a direction other than the removal direction X2. If the wires are pulled in that direction, a pulling force via the lead wires 9w is converted to a force in the removal direction X2 of the socket connector 7 in order to smoothly remove the socket connector 7 without having to pry off the connectors.
In FIG. 17, the base connector 6 is provided with a base housing 60 comprising a base 62 fixed along the attachment face 51, a pair of sidewalls 62a, 62b disposed in upright position on left/right sides of the base 62, and a rear wall 62c. The base 62, the pair of sidewalls 62a, 62b, and the rear wall 62c are combined to form the recess 61.
In FIG. 17, the recess 61 houses a plurality of (e. g., three) plane contacts 8 (hereinafter, referred to as plane connection terminals 8) parallel to the sidewalls 62a, 62b. In FIG. 19, the plane connection terminals 8 are inserted into fixing holes formed in the base 62 and held by the base 62 and the rear wall 62c. The plane connection terminal 8 includes a substantially rectangular main body 80 and a lead portion 8r extending from the lower end to rear side of the main body 80. The main body 80 has a contact portion 81 protruding into the recess 61 (refer to FIG. 19).
When both connectors 6, 7 are in a mated condition, the plane connection terminal 8 is sandwiched by a pair of contact strips 91a, 91b included in the socket contact 9 of the socket connector 7 from both sides of the terminal and held by the strips (refer to FIG. 20).
In FIG. 17, the rear wall 62c is provided with a pair of vertical grooves 64a, 64b along the pair of the sidewalls 62a, 62b. When both connectors 6, 7 are in a mated condition, the pair of vertical grooves 64a, 64b act as seats for a pair of vertical ribs, not shown, formed in the socket connector 7.
In FIG. 17, a pair of mating grooves 63a, 63b extending from the bottom to top of the recess 61 are provided in the inner faces of the pair of sidewalls 62a, 62b. The pair of mating grooves 63a, 63b act as seats for a pair of two-step ribs 73a, 73b formed on and protruding from both sides of the socket connector 7 (refer to FIG. 18). The pair of two-step ribs 73a, 73b include thick upper ribs 73a1, 73b1 and thin lower ribs 73a2, 73b2.
In FIG. 18, the pair of lower ribs 73a2, 73b2 are of a triangular shape and have a width gradually reduced from the top to bottom of the rib, and the inclined faces of the ribs form cam faces for slidable engagement with inclined faces (refer to FIG. 17) formed on the pair of mating grooves 63a, 63b. This allows conversion of a pulling force causing the socket connector 7 with the lead wires 9w to be pulled in the front direction Y into a force in the removal direction X1 of the socket connector 7.
In FIG. 17, a pair of mating projections 66a, 66b facing each other are provided on the upper front portions of the inner faces of the pair of sidewalls 62a, 62b. When both connectors 6, 7 are in a mated condition, the pair of mating projections 66a, 66b mate with a pair of mating depressions 76a, 76b (refer to FIG. 18) provided on both side faces 72a, 72b of a socket housing 70, thereby allowing both connectors 6, 7 in a mated condition to be held with a predetermined holding force. Further, the pair of mating projections 66a, 66b and the pair of mating depressions 66a, 66b form a locking mechanism.
Note that in FIG. 17, a pair of reinforcing tabs 67a, 67b as a metallic reinforcing member are pressed into press-fit grooves formed in the lower front portions of the base housing 60 and a part of the reinforcing tab is exposed from the corresponding side face of the base housing 60 so as to be solder-bonded to the attachment face 51 of the print board 5.
In FIG. 18, the socket connector 7 comprises in its front section a projection 72c provided on the upper face, i.e., a pressing face of the socket housing 70 and protruding so as to correspond to the position of the socket contact 9, and the above-described pair of two-step ribs 73a, 73b formed on and protruding from both side faces of the socket housing 70, respectively. Pressing the surface of the projection 72c allows the socket connector 7 to be mounted onto the base connector 6.
In FIG. 19, the base housing 60 of the base connector 6 is provided with the plane connection terminals 8. On the other hand, the socket housing 70 of the socket connector 7 is provided with the socket contacts 9. For example, the base housing 60 is provided with three plane connection terminals 8 disposed in parallel to one another and the corresponding three socket contacts 9 are disposed in parallel in the socket housing 70. The lead wires 9w press-bonded to pressing portions 92 of the socket contacts 9 extend from the socket housing 70.
In FIG. 19, the plane connection terminal 8 comprises the main body 80 pressed into the base housing 60 and fixed thereto, and the contact portion 81 protruding into the recess 61 formed in the base connector 6. On the other hand, the socket contact 9 is inserted into and held by a compartment 71 having the shape of a square pole. A portion of the compartment 71 corresponding to the contact portion 91 of the socket contact 9 is opened toward the recess 61.
In FIG. 19, the socket connector 7 is inserted toward the recess 61 formed in the base connector 6 and mates with the base connector 6. Then, the plane connection terminal 8 and the socket contact 9 forming a pair are electrically connected.
In FIG. 20, the socket contact 9 has a pair of contact strips 91a, 91b extending in parallel and facing each other, and the contact strips are provided with contact points 91c, 91d made of projections protruding so as to face the corresponding opposing face of the corresponding one of the pair of contact strips 91a, 91b. 
In FIG. 20, the contact portion 81 (refer to FIG. 19) of the plane connection terminal 8 of the base connector 6 is inserted into a gap S between the pair of opposing contact points 91c, 91d and the plane connection terminal 8 is sandwiched and elastically held by the pair of contact strips 91a, 91b, thereby allowing for intimate contact between the plane connection terminal 8 and the socket contact 9.
However, it has been required that the socket connector 7 shown in FIG. 18 is mounted at a substantially lower height. Further, the mounting height of the socket connector 7 is substantially determined by the distance over which the pair of contact strips 91a, 91b provided in the socket contact 9 extend. It has been required that the structure of the socket contact is changed in order for the socket connector to be mounted at a substantially lower height.
In order to solve the aforementioned problems, the structure of the socket contact is changed to allow the socket connector to be mounted at a substantially lower height and further the base contact to be mounted at a substantially lower height. In this case, it becomes impossible to allow the recess provided in the base connector to have a sufficient depth. Further, when such connectors having a lower height are used, it would be undesirable and expected that the lead wires extending from the socket connector act to cause the movement of the socket connector about a point of support, which movement is associated with a pair of locking mechanisms installed at both sides of the socket connector. This implies that the movement of the socket connector eventually leads to contact failure.
Therefore, there is a need for a more reliable electrical connecter having a locking mechanism for securely maintaining engagement between both the extremely small connectors having a lowered height, one of which is a base connector fixed to a print board and the other of which is a socket connector inserted into/removed from the base connector and having lead wires. Thus, it can be concluded that the foregoing is the subject of the invention.
In consideration of the above-mentioned problems, an object of the invention is to provide a compact sized electrical connector having a low height and equipped with a locking mechanism for securely maintaining engagement between both connectors, one of which is a socket connector inserted into a recess formed in a base connector, without being affected by lead wires extending from the socket connector.